Lycopene is a carotenoid with 40 carbon atoms, which is responsible for the red colour of many fruits and vegetables. From a chemical perspective, lycopene is an isoprenoid hydrocarbon consisting of 8 units of isoprene forming a symmetrical chain. Its structure contains 11 conjugated double bonds and 2 non-conjugated ones. Therefore, it has a greater number of double bonds than any other carotenoid, including β-carotene. This unusual structure confers it some special characteristics. Hence, for example, lycopene can be used as a coloring or dye and is much more efficient as a pigment than β-carotene. Hence, it is noteworthy that lycopene covers a broader colour range, that going from yellow, passing through orange, to an intense red color. Moreover, it has a stronger colour intensity in the yellow-orange colour range, 6 to 8 times greater than that of β-carotene. Its use as a food coloring has been authorized, and its European code is E-160d. However, its use today is not very widespread owing to its high price.
Although the use of lycopene as a coloring is interesting, undoubtedly its most noteworthy property is its antioxidant capacity. In the organism, oxidations occur on a cellular level due to the presence of free radicals and, especially, the singlet oxygen. These undesirable reactions are highly dangerous since, like other radical reactions, they are autocatalytic, i.e. they are self-propagated via a chain reaction process. This can produce irreversible damage in essential cell components (membrane lipids, nucleic acids etc.) in a process known as oxidative stress that is associated with cellular ageing, degenerative diseases, blocking of arteries and the appearance of different types of cancer (S. Toyokuni, K. Okamoto, J. Yodoi and H. Hiai (1995), “Persistent oxidative stress in cancer”, FEBS Letters, Volume 358(1), 1-3; K. Senthil, S. Aranganathan and N. Nalin (2004), “Evidence of oxidative stress in the circulation of ovarian cancer patients”, Clinica Chimica Acta, 339(1-2), 27-32).
Lycopene has a high antioxidant potential (Burton G. W. (1989), “Antioxidant action of carotenoids”, J. Nutr. 119, 109-111; Diplock A. T. (1991), “Antioxidant nutrients and disease prevention: an overview”, Am. J. Clin. Nutr. 53, 189S-193S; Wertz K., Siler U. and Goralczy R. (2004), “Lycopene: modes of action to promote prostate health”, Archives of Biochemistry and Biophysics, 430(1), 127-134) that makes it an excellent inactivator of the singlet oxygen and free radicals (Di Mascio P., Murphy M. E. and Sies H. (1989), “Lycopene as the most efficient biological carotenoid singlet oxygen quencher”, Arch. Biochem Biophys., 274, 532-538; Di Mascio P., Murphy M. E. and Sies H. (1991), “Antioxidant defense systems: The role of carotenoids, tocopherols and thiols”, Am. J. Clin. Nutn., 53, 1945-2005). This natural pigment acts as an antioxidant agent, transferring electrons to the free radicals, deactivating them. The lycopene radical formed is stable owing to its large number of double bonds, which permit it to stabilize by resonance. This antioxidant potential confers it an anticarcinogenic activity and a preventive action against cardiovascular diseases. The studies of Giovannucci et al. (Giovannucci E. (1998), “Tomatoes, tomato-based products, Lycopene, and cancer: Review of the epidemiologic literature” 1999, J. Nat. Cancer Inst., vol 91, 317-331; Giovannucci E., Ascherio A., Rimm E. B., Stampfer M. J., Colditz G. A. and Willett W. C. (1995), “Intake of carotenoids and retinol in relation to risk of prostate cancer”, J. Natl. Cancer. Inst., 87, 1767-1776), indicate that consumption of tomatoes, tomato sauce and pizza is directly associated with a reduced risk of developing different types of cancer, such as cancers of the digestive system and prostate cancer.
Cardiovascular diseases are among the most common causes of death in western countries. It was initially considered that one of the main risk factors corresponded to the presence of high blood cholesterol levels. Later, it was suggested that the key step in atherogenesis is oxidation of cholesterol by the action of free radicals. It has been shown that the incidence of cardiovascular diseases is strongly correlated with plasma levels of carotenoids, and lycopene is especially effective at clearing away peroxide radicals under physiological conditions and preventing the oxidation of low molecular weight lipoproteins (LDL) to their atherogenic form.
More recently, the possible preventive effect of lycopene against diseases such as diabetes type II and osteoporosis has been studied. It appears that oxidative processes are also involved in these diseases, thus lycopene could also have a beneficial effect here.
Because of its remarkable properties, lycopene is also a true nutraceutical product. A nutraceutical product can be defined as “a food product, or part of a food, that confers medical or health benefits, including the prevention and treatment of diseases” (De Felice S. L. (1991), “The nutraceutical initiatives: A proposal for economic and regulatory reform”, Ed. The Foundation for Innovation in Medicine).
Lycopene is presented on the market as a solid, as crystalline lycopene dispersed in a liquid in which it is insoluble (water, ethanol or polyoles) or as an oleoresin.
Numerous patents and patent applications described how to obtain lycopene and lycopene-enriched products. Probably, patent application WO 96/13178 has had the greatest industrial application. This patent is noteworthy for its simplicity since it describes a process for preparing a lycopene concentrate by reducing the size of the lycopene crystals (present in the chromoplasts) in a medium which essentially does not dissolve lycopene (water, ethanol or polyoles). In other words, this method is based on using polar solvents, that do not dissolve lycopene (apolar compound) but, that “literally” pull with them the crystals that are present naturally in the plant chromoplasts. However, to obtain a lycopene-rich oleoresin, in this patent WO 96/13178 organic solvents are used, specifically acetone and ethyl acetate. In fact, all the oleoresins currently on the market are prepared using organic solvents, since these solubilise the apolar substances. The organic solvents most used include hexane, acetone and ethyl acetate (see, for example, the documents EP 671461 A1, EP 1487282 A1, EP 1103579 B1, EP 0818225, WO 97/48287, U.S. Pat. No. 5,837,311). Since organic solvents present some degree of toxicity, both for the workers handling these products and also for consumers it is recommendable not to use organic solvents to make nutraceutical products or products of pharmacological interest, since their total removal cannot be guaranteed. Neither does the use of synthetic lycopene ensure the absence of organic solvents, because they are used in the synthesis process.
Since lycopene is an apolar substance, it is also soluble in supercritical fluids (Sabio E., Lozano M., Montero de Espinosa V., Coelho V. J., Pereira A. P., and Palabra A. F. (2003), “Lycopene and other carotenoids extraction from tomato waste using supercritical CO2”, Ind. Eng. Chem. Res., 42, 6641-6646). Recently, a patent application was presented (WO 02/40003) based on the extraction of lycopene using supercritical CO2. After the supercritical extraction, the mixture is depressurized, and CO2 passes to the gaseous state, obtaining an extract rich in lycopene free of solvents. This method clearly presents some advantages compared to the use of organic solvents. However, it is noteworthy that the process is considerably more expensive. Moreover, because of the greenhouse effect of CO2, precautions must be taken to avoid emitting this compound.
With the new invention presented here, lycopene-rich products can be obtained without using any intermediate chemical agent, organic solvents, supercritical fluids or dispersants.
The classical approach, to date, to obtain lycopene-enriched formulations has focused on obtaining oleoresins from a lycopene-enriched product by extraction with an organic solvent, the presence of which is not desirable in the final formulation. After carrying out the extraction, the organic solvent is eliminated (although never completely) and the extract obtained is diluted in oil or fat that is used in the final formulation.
The present inventors have now developed an alternative process to obtain lycopene-enriched formulations by direct solubilization, based on the liposoluble nature of the lycopene. This process directly produces the desired formulation without using organic solvents or other intermediate chemical agents, supercritical fluids or dispersants, for example, as mentioned previously.
Moreover, this direct solubilization process allows to obtain in a simple and inexpensive way, lycopene-enriched formulations with an appropriate contents of lycopene (of around 500-1000 ppm) to permit it to be dosified easily and safely. Indeed, the lycopene-enriched formulations known in the state of the art of the technique have much higher lycopene concentrations (30,000-60,000 ppm) making it very difficult for these to be dosed for regular and controlled intake. Recent studies suggest that a high intake of antioxidants may not merely not be beneficial but may even be harmful, since their antioxidant action depends on their concentrations, and high concentrations may no longer be antioxidant but can become pro-oxidants (E. R. Miller, R. Pastor-Barriuso, D. Dalal, R. A. Riemersma, A. Appel and E. Guallar (2005); “Meta-Analysis: High-dosage vitamin E supplementation may increase all-cause mortality”. Ann Intern Med. 142: 37-46).
In this new process, a starting material rich in lycopene is directly exposed to the solubilising action of an oil or fat that is to be used in the final formulation, obtaining, in a simple and rapid way a lycopene-enriched product with the appropriate proportion of lycopene that can be easily and safely administered without using any intermediate chemical agent. That is, the preparation of this product only uses the lycopene source and the oil or fat to be present in the final formulation or, in other words, the product obtained is exempt from any organic solvent or chemical agent that is strange to the final formulation.
Moreover, when the extractant lipid is an edible oil or fat, the resulting solid residue produced after the extraction can be consumed, since it has not been treated with organic solvents.
Therefore, its advantages over the conventional indirect method mentioned previously that uses organic solvents, are numerous, as any skilled person in the art can easily deduce. These correspond to:
1) An absence of chemical pollutants, mainly organic solvents, hence the formulation obtained has a greater added value.
2) A simpler process: less costs, greater rapidity, less components used in the process, less energy consumption, less steps required to obtain the final formulation, etc.
3) Adequate lycopene content: easy and safe to dosify, direct consumption of the product in any form of presentation.
4) Less environmental pollution. The organic solvents are pollutants as well as the gases used in the supercritical fluids.
5) Nutritionally more beneficial formulations than those obtained by simply mixing pure lycopene with the oil or fat: additional content of other extracted phytochemicals (carotenoids, sterols, etc.) with antioxidant potential and synergic action between them, increased when using olive oil as an extractant lipid (rich in tocopherols). Additionally, these phytochemicals are undegraded, in contrast to those extracted by the extraction technique using solvents, in which the aggressive treatments used to eliminate the solvent notably degrade all the phytochemicals, including lycopene.
6) The solid residue that remains after the extraction has a high added value, since it has not undergone any chemical treatment and can be used directly to produce other products (sauces, creams, purees etc), having a high nutritional value and being a good source of soluble dietary fiber and minerals.